Introduction - Mapletree Stealth Max User Manual

Introduction

The Mapletree Audio Design Stealth Max vacuum tube monobloc power amplifier
features:
♦ A low distortion Class AB
beam power tubes delivering a conservative 50 W continuous power. A triode/ultra-
linear mode switch to permit experimentation with different sonic presentations. The
triode power rating is about 20 W.
♦ An output transformer that is an exact replica of the Dynaco A431S used in the
original Mk III amplifier. The power transformer is conservatively rated and can
deliver the current required for maximum power output. Soft startup is assured
through use of a 5AR4/GZ34 rectifier tube.
♦ A driver module based on the Mapletree Special Red SR-70 board for the Dynaco ST-
70. It employs octal tubes in a Mullard-type circuit with 6SJ7 pentode voltage
amplifier and a 6SN7 long-tail phase inverter.
♦ Wide frequency response: 20 Hz–20 kHz –1 dB at 50 W output.
♦ Adjustable fixed bias for optimum performance with any matched pair of output
tubes.
♦ Stainless steel chassis and high quality components and hardware used throughout.
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ultra-linear output stage employing easily obtained KT88
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